on Sale - $55/pr (drivers & XO)

[Herman Trivilino]

Re: SICK - SICK - SICK . . .

For the low pass though, besides your 1.4mH coil, I'd like to see you use a 20n resistor and a 4uF cap on the Zobel. This will help to pull down that 3dB hump aroudn 2k that I saw in Grinnell.

Ok, the Zobel in the low pass in Post #18 has a 4 µF cap and a 4 Ω resistor. I'll just swap the 4 Ω for a 20 Ω. Thanks.

Just pulled the trigger. I got free shipping. After subtracting the cost of a spool of wire and a wire stripper, and applying the $5 coupon, the parts total about $75. All I need to add are the cabinets and the port tubes.

If I decide later to go with one of the upgraded crossovers I'll not have wasted but a few pennies on the budget resistors and caps. I've been waiting a long time to make this decision, and was getting scared that if I waited too much longer the sale on the drivers would end.

[cliffburge]

Re: on Sale - $55/pr (drivers & XO)

Would this in the "ntn" configuration be a good candidate for a center channel?? I am stuck with an area 7.5 inches high between my tv and the fireplace to make a center channel. It could be built with all three drivers pretty much touching each other to keep ctc spacing down to a minimum. Of course it would be with the woofers on the bottom and the tweeter on top of the two. I have a small living room and off axis is an issue. Also if it seems like it may make a good center would there be any changes to the crossover with it stuck between two reflective surfaces and pretty much right up against the wall.



ports could be front mounted or side mounted- hmmm with the ports on the side it would keep the dust off of the top of the fireplace!! ha :D


Any help with this would be much appreciated, the more I learn, the more I find out that the "heart and soul" -aka the crossover is hard to design properly.


Cliff


Cliff

[Chris Roemer]

Re: on Sale - $55/pr (drivers & XO)

Would this in the "ntn" configuration be a good candidate for a center channel?? I am stuck with an area 7.5 inches high between my tv and the fireplace to make a center channel. It could be built with all three drivers pretty much touching each other to keep ctc spacing down to a minimum. Of course it would be with the woofers on the bottom and the tweeter on top of the two. I have a small living room and off axis is an issue. Also if it seems like it may make a good center would there be any changes to the crossover with it stuck between two reflective surfaces and pretty much right up against the wall.



ports could be front mounted or side mounted- hmmm with the ports on the side it would keep the dust off of the top of the fireplace!! ha :D


Any help with this would be much appreciated, the more I learn, the more I find out that the "heart and soul" -aka the crossover is hard to design properly.


Cliff


Cliff

Well, horizontally, the ntn has a spread of about 6" C-C between woofers. To make a good center, with that spacing, it really should cross almost down at 2k, and it doesn't.

Putting the woofers right up against each other, with tweeter above, is better, if you use the latest XO from my album, which has an Fc in the vicinity of 3.4k.

Ideally, in a box 7.5" high, I think you could just do the Nano Neo, TM, with the box oriented wide. How about that?

[Herman Trivilino]

Re: on Sale - $55/pr (drivers & XO)

Would this in the "ntn" configuration be a good candidate for a center channel?? I am stuck with an area 7.5 inches high between my tv and the fireplace to make a center channel. It could be built with all three drivers pretty much touching each other to keep ctc spacing down to a minimum. Of course it would be with the woofers on the bottom and the tweeter on top of the two.

You have 7.5 inches of height? And what's the restriction on the width? I don't see why you'd have to limit the ctc spacing?

[cliffburge]

Re: on Sale - $55/pr (drivers & XO)

Originally I was thinking that 1 4" woofer would not be loud enough for home theater use, and that is why I was pondering a "sideways ntn".
I have noticed (after reading your last post) that the ntn version has woofers in series, not having any more sensitivity, but more power handling leading to a little more spl.
I included a pic of the Idea of the center channel just to make sure I am explaining myself correctly.
I have a "75" watt per channel Yamaha receiver that I may challenge the power output every now and then.

Will the regular mt handle the power that I may be able to give it and sound good? I do realize that the center is crossed over, but I was hoping to use the lower crossover freq from my center, aka "large" in setup of receiver.

With the layout in the pic, will this be a compromise to off axis listening, making it a "good" center, or is the xover freq still too high for that format and it's ctc spacing?


Cliff

[Chris Roemer]

Re: on Sale - $55/pr (drivers & XO)

Originally I was thinking that 1 4" woofer would not be loud enough for home theater use, and that is why I was pondering a "sideways ntn".
I have noticed (after reading your last post) that the ntn version has woofers in series, not having any more sensitivity, but more power handling leading to a little more spl.
I included a pic of the Idea of the center channel just to make sure I am explaining myself correctly.
I have a "75" watt per channel Yamaha receiver that I may challenge the power output every now and then.

Will the regular mt handle the power that I may be able to give it and sound good? I do realize that the center is crossed over, but I was hoping to use the lower crossover freq from my center, aka "large" in setup of receiver.

With the layout in the pic, will this be a compromise to off axis listening, making it a "good" center, or is the xover freq still too high for that format and it's ctc spacing?


Cliff

Like I say, the ntn with woofers pulled together (nearly touching) with the ND20 above will use about the same height as the TM version, and I THINK you could squeeze that into 6" of internal height. You need to roundover the backside of the baffle for the 105s, so they can breathe. You might also have to clearance the inside of the bottom panel as well.

ROT is in a traditional (vertical) MTM, the cross point should be no higher than the SOS (speed of sound, 13,500 ips) divided by the C-C distance between the tweeter and EITHER woofer. On the Nano Neos this is 3", giving you <= 4.5 kHz. The Fc is lower than this, so that's no problem.

In a horizontal MTM, the cross point should be no higher than the SOS divided by the C-C distance between the WOOFERS, which would be 6", making <= 2.2k, which won't happen with the ND20. BUT, putting the woofers together (like your diagram shows) with the tweeter above, should give you a C-C spread of 4"+, with an Fc <= 3.4k, which you'll get if you use the latest (and probably last) XO version, from my "album".

The difference is that there is "comb filtering" occuring VERTICALLY off-axis from the tweeter in an MTM, which isn't the problem (with the tweeter at ear height) that it is when it occurs horizontally off-axis (wth the MTM on its side) with a bunch of people lined up on a couch, for instance.

Chris

[cliffburge]

Re: on Sale - $55/pr (drivers &amp; XO)

Thank you for your input. I draw out a plan and see if I can get enough breathing room for these woofers. Yet another aspect that I did not think of, I guess that is why it is called designing!!

Thanks again for your input!




Cliff

[Tweaker]

Re: on Sale - $55/pr (drivers &amp; XO)

In a horizontal MTM, the cross point should be no higher than the SOS divided by the C-C distance between the WOOFERS, which would be 6", making <= 2.2k, which won't happen with the ND20.

Hi Chris,
new guy jumping in here.
I wonder, what if the tweeter were changed to one that can take the lower xover? I built an MTM design using the 5" Jamo 20499 $4.50 driver and the Vifa DQ25SC05-04 tweeter. It was based somewhat on the Zaph ZA5.3c design.
I've been really happy with the center channel horizontal coverage and the sound for HT use is really good. Thing is, I want more low end punch, especially for music and I hope to make the center channel narrower so it fits below the screen.
I've attached some initial layouts of where I'm heading. My budget may still stay below $55 cause I already have the Vifa tweeters. (Is that cheeting?)
I'd appreciate your thoughts on my layout and the use of the Vifa tweeter. I plan on setting the xover around 1,800 Hz for the center channel. It could go higher for the L/R, but we'll see. I need to place the L/R right up next to the screen and the lower xover seems to work nicely that way.
I'll also play with the BSC after they're built.

I've decided on a 0.5cu Ft vented enclosure for the center tuned to around 45Hz and a 0.7cu Ft vented enclosure tuned to around 45Hz for the L/R.
Thanks for your input!
I'll keep everyone informed as to how things proceed.
G.

[Tweaker]

Re: on Sale - $55/pr (drivers &amp; XO)

Moving forward with the geedee center channel version of Chris's ntn, I've designed the xover at 1800hz with a hefty L-Pad for the tweeter. I'll need to check this out further... There's a 10dB difference between the ND105 and the Vifa tweeter.

So, a question, when running two similar drivers in parallel, as I understand it, you add 3dB to the overall output. Does the same apply when running in series, or does the increase in Re decrease the effect of adding a 2nd driver?

Also, do you get the same low distortion as running the drivers in paralel?

Based on previous experience with this tweeter in a MTM configuration, I'm hoping with this low of a cross over I should get fairly good horizontal coverage, or at least good enough for my application.

http://techtalk.parts-express.com/attachment.php?attachmentid=13569&stc=1&d=1295688733

Tweeter
C1 12.5 uf
L1 .63 mh
R1 2.74 ohm 10 W
R2 1.85 ohm 5 W
T-1 Vifa DQ25SC05-04
Woofer
L2 1mh
C2 7.81 uf
R3 9.25 ohm 10 W
C3 18.23 uf
W1 & W2 Dayton ND105-4



I haven't planned on any baffle step at this time because the speakers will be right up against other surfaces. If it's needed, I'll work this out after I build them and test them out.

I appreciate any input on this from those more knowledgeable. After I hear back from a couple of you more experienced folks, I'll pull the trigger on ordering up the ND105's. Now PE, please don't run out of them!

Thanks,
Greg D.

[Chris Roemer]

Re: on Sale - $55/pr (drivers &amp; XO)

Moving forward with the geedee center channel version of Chris's ntn, I've designed the xover at 1800hz with a hefty L-Pad for the tweeter. I'll need to check this out further... There's a 10dB difference between the ND105 and the Vifa tweeter.

So, a question, when running two similar drivers in parallel, as I understand it, you add 3dB to the overall output. Does the same apply when running in series, or does the increase in Re decrease the effect of adding a 2nd driver?

Also, do you get the same low distortion as running the drivers in paralel?

Based on previous experience with this tweeter in a MTM configuration, I'm hoping with this low of a cross over I should get fairly good horizontal coverage, or at least good enough for my application.

http://techtalk.parts-express.com/attachment.php?attachmentid=13569&stc=1&d=1295688733

Tweeter
C1 12.5 uf
L1 .63 mh
R1 2.74 ohm 10 W
R2 1.85 ohm 5 W
T-1 Vifa DQ25SC05-04
Woofer
L2 1mh
C2 7.81 uf
R3 9.25 ohm 10 W
C3 18.23 uf
W1 & W2 Dayton ND105-4



I haven't planned on any baffle step at this time because the speakers will be right up against other surfaces. If it's needed, I'll work this out after I build them and test them out.

I appreciate any input on this from those more knowledgeable. After I hear back from a couple of you more experienced folks, I'll pull the trigger on ordering up the ND105's. Now PE, please don't run out of them!

Thanks,
Greg D.

With a different tweeter, different XO, and different boxes/tunings, you're not really building ANY "version" of my ntn. You're just designing a new speaker using a pair of the same woofers, that's all.

I'm not sure, why given the opportunity to build 3 identical L/C/Rs, that you're changing box sizes and tunings between them. Personally, I wouldn't.

I don't have F/Z data for THAT tweeter. I don't really even see that EXACT model on Zaph's site. It looks to be fairly similar to the ND20-6 that I used, except I think it's about an inch larger in diameter, and more expensive. I only saw one source of an Fs for it, but it was 1.7k or so (IIRC). Normally, I'd cross that an octave higher, at 3.4k or more.

With your horizontal C-C distance being 7", I think your aim of 1.8k for an Fc is a good one, just not sure that your tweeter will be happy there.

On my Nano Neos / ntn - I've got the ND20 padded about 9-10dB.

Two (typically 8 ohm) drivers in parallel, net you a +6dB gain in sensitivity. Two in series show no net gain.

Excursion (given the same output level) will be halved in either case, compared to a single driver.

Chris

[Tweaker]

Re: on Sale - $55/pr (drivers &amp; XO)

Hi Chris,
Thanks for the input.
I see I put the wrong part number in for the Vifa Tweeters. They're actually Vifa DQ25SC16-04. I think I paid $13 for them.

The reason I was looking to use the Vifa tweeters, is I've already got them in use on an MTM arrangement with the Jafo 5" speakers. They seem to be happy with fc at 1.8K, but then again, I may not be aware of the problem if there is one.
And for the center channel, the Xover being that low seems to give me a very nice horizontal coverage. The only thing I don't particularily like about my existing MTM setup is the Jafo's. They're nice enough in the mid range but they don't do well at the low end. It's just muddy sounding. (1.5mm XMAX?)

But, yeah, you're right. It's not fair to compare what I'm doing, cause it realy is a different speaker.

I'm not sure, why given the opportunity to build 3 identical L/C/Rs, that you're changing box sizes and tunings between them. Personally, I wouldn't

.

The reason for the difference between L/R and Center is because I can't fit the full size MTM under my screen and I still like the idea of the full size version for L/R when listening to music. It's also a compromise in the interest of domestic tranquility.

My HT setup is on a TV stand with a 4" solid bar between top of the stand that the flat panel sits on. Below that bar is an opening just shy of 5-7/8" till the first shelf. The maximum width (or height) I could fit is 5-3/4" without serious modification, I've got 14" deep and side to side width isn't really a problem on the shelf the center channel sits on.

I'll take another look with the ND20 and see how things work out. If I can squeeze it all in a 5-3/4" wide cabinet, I think this is a go. At this price, if the center doesn't work out and give me enough horizontal coverage, I've really only lost some MDF. I'll just build a set of nt surrounds, nt desktops, nt garage speakers!

So, it's back to the drawing board with ntn (no caps)
Thanks for the input,
Regards,
Greg D.

[JustinL42]

Re: on Sale - $55/pr (drivers &amp; XO)

Got all of the panels cut for mine past weekend, everything fits together great. Currently have the boxes taped together with just the woofers hooked up full range. I've got to say the bass response is impressive condsidering no doubt I've got air leaks everywhere. Cant wait to get them finished.

JustinL42

[isaeagle4031]

Re: on Sale - $55/pr (drivers &amp; XO)

I should be starting my ntn towers this week. Parts are ordered. Thanks Chris for your help. If the budget allows I will be making a pair of the nanos for the surrounds as well

[JustinL42]

Re: on Sale - $55/pr (drivers &amp; XO)

Making some progress now. The flush mount for the terminal cups I routed freehand. The port holes and the hole for the terminal cups were freehand with a jigsaw as was the hole for the woofer. Tweeter hole was done with a hole saw. All the panels were cut on a table saw and then I used a router table for the first time to do the rabbets. My my previous and first major build was a pair of Shamrock SE2's from the now defunct Shamrock Audio.

http://s18.photobucket.com/albums/b1...20Neo%20Build/














JustinL42

[JustinL42]

Re: on Sale - $55/pr (drivers &amp; XO)